There are four major steps in risk assessment, which is the
determination of the relationship between predicted exposure and adverse
The four steps are:
1. Hazard identification
2. Dose-response evaluation
3. Exposure assessment
4. Risk characterization
Toxicity is the inherent potential or capacity of a chemical
(generally established from a dose-response relationship) to cause adverse effects
in a living organism that seriously damages its structure or function or
results in death. Toxicity testing (for humans: toxicity; for the environment:
ecotoxicity) is usually carried out through controlled studies on living
organisms, isolated tissues, cells or cellular components. Toxicity is
generally influenced by the unique physico-chemical properties of the chemical.
Examples of toxicity tests that are pertinent to human health hazards relate to
skin and eye irritation, sensitization, carcinogenicity, reproduction toxicity.
Examples of ecotoxicity tests that are pertinent to ecological hazards relate
to acute and chronic toxicity to fish and algæ.